1. Field of the Invention
The present invention relates to a Christmas bulb structure, particularly to an improved Christmas bulb structure.
2. Description of the Related Art
Christmas bulb structures are usually wound around a Christmas tree, or hang on walls or below eaves, and the flickering of Christmas bulb structures can create warm and happy ambiance for the festival.
There are two kinds of Christmas bulb structures. One of them is the primary bulb, and the other is the secondary bulb. The light string formed of secondary bulbs is constantly lit on or lit off, which lacks variety and brings about a dull sensation. Therefore, there is a kind of control box used for controlling the secondary bulbs to create a diversified lighting effect. However, the cost of the light string is raised because of the high price of the control box.
Referring to FIG. 1, the primary bulb has a bulb shell 2, and two conductive wires 4, including a first conductive wire 42 and a second conductive wire 44, extend from the interior of the bulb shell 2 to the exterior of the bulk shell 2; an insulator 6 separates those two conductive wires 4; an elastic platelet 8 disposed between those two conductive wire 4 is inserted into the insulator 6; both ends of a tungsten filament 10 separately connect the elastic platelet 8 and the first conductive wire 42; the second conductive wire 44 does not contact the elastic platelet 8 normally, but when the primary bulb is electrically powered, the elastic platelet 8 contacts the second conductive wire 44, and the current flows through the tungsten filament 10, and the tungsten filament 10 is lit on; once the elastic platelet 8 is heated to a given temperature, the elastic platelet 8 springs away from the second conductive wire 44, and the elastic platelet 8 no more contacts the second conductive wire 44, and thus, the light of the primary bulb ceases; as there is only one current path in the primary bulb, and as the light string is formed via connecting the primary bulb with the secondary bulbs in series, the in-series connected secondary bulbs also cease simultaneously. Consequently, the entire light string is lit on or lit off synchronically with the primary bulb, which presents a visual effect lacking variety.
Accordingly, the present invention proposes an improved Christmas bulb structure to overcome the abovementioned problem.